4.1 Defining the Atom Flashcards
(14 cards)
What is an atom?
An atom is the smallest particle of an element that retains its identity in a chemical reaction
Democritus reasoned that atoms were ……………………..
indivisible and indestructible
Democritus depended on ………………….
No experiment, although his theory was right it didn’t explain chemical behavior
Democritus’s theory lacked experimental support because democritus’s approach was not based on…………….
Scientific method (so it lacked both experiments and scientific method)
Who was an English chemist and school teacher?
Dalton
When did dalton come?
2000 years after democritus
Dalton depended on using……………
Experimental methods (Experiments and scientific method)
Dalton transformed democritus ideas on atoms into a……………..
Scientific theory
What is the difference between a mixture and a compound?
A Mixture: Physical mix
A Compound: Chemical mix by joining together
What is Dalton’s atomic theory?
1.)All elements are made up of atoms
2.)Atoms of the same element are same, and Atoms of different element are different
3.)Mixture:Physical mix of different atoms and different elements
Compound:Chemical mix or combine of different atoms and different elements
4.)Chemical reaction: by joining atoms or rearranging atoms , the atoms of one element never change to atoms of different or another element as a result of a chemical reaction.
Describe the atom’s size:
1.)Very small
2.)100,000,000 atoms of copper take 1cm long
3.) The Radii of atoms range from 5x10^-11m to 2x10^-10m
How can we see electrons?
Using SEM(scanning electron microscope) microscope
Who discovered the atom first?
Democritus then Dalton
Democritus was the first one to ………….
Suggest the presence of the atoms
